Hardy-Weinberg calculator
Enter one known frequency to get the rest, with the steps shown.
Use decimals, so 4% is 0.04. Assumes a two-allele gene in Hardy-Weinberg equilibrium: p + q = 1 and p² + 2pq + q² = 1.
The two equations
For a gene with two alleles, p is the frequency of the dominant allele and q is the frequency of the recessive allele, so p + q = 1. Genotype frequencies follow p² + 2pq + q² = 1.
A common problem gives the share of people showing the recessive trait. That is q², so q is its square root. The model assumes random mating, no selection, no mutation, no migration, and a large population.